Spiritual rangers (Armadyl) are ghostly followers of Armadyl which are only found in Armadyl's Eyrie across the deep chasm in southern section of the God Wars Dungeon. 70 Ranged is required to cross the chasm.

As long as you are using Ranged and have an Armadyl item or Shard of Zaros equipped to prevent aggression, these rangers shouldn't pose too much of a threat to most players and can be easily killed.